Chromophobe renal cell carcinoma is a malignant distinct
subtype of renal cell carcinoma and comprises approximately 5% of neoplasms of
the renal tubular epithelium, originating in the distal nephron. It has
been described as having a compact growth pattern of large tumor cells, having a
translucent and reticular cytoplasm and distinct cell borders.

This type of renal cancer was described first in 1989 by Dr. Kovacs. Unlike most other RCC, these lesions are hypovascular or vascular on renal arteriography. The tumors of this type have different biologic and cytogenetic characteristics as compared with nonpapillary RCC. The tumor is classified as a true papillary RCC if at least 75% of the neoplasm shows papillary growth pattern, with remaining tumor having a tubulopapillary architecture composed of granular cells.

The mean age of patients diagnosed is 59, as reported in one
study. It is diagnosed in man as often as women. The only known risk
factor that I found in the literature was a congenital disease known as
Birt-Hogg-Dubé Syndrome (BHD). Patients diagnosed with this cancer
should always be tested for this condition.

Although most patients show no symptoms of this cancer, some patients have
presented with flank pain,
followed by hematuria and/or a palpable mass. Because of it's rarity, pathologists
may not familiar with this neoplasm or the neoplasm my have an atypical
morphology. Always request a second, independent, pathology opinion.
Radiographically, the tumor may show up as a hypervascular lesion with a central
scar.

This cancer may have a slightly better prognosis in grade 3 and 4
than other renal cell carcinomas, but outcome data are limited. Tumors are
more often localized to the kidney (stage I) at diagnosis. Histologic tumor
necrosis was an indicator of a poorer prognosis.